- Manticore Arms, Inc.
- Marconi Armory
- Marlin
- MasterLock
- MasterPiece Arms
- MaTech Solutions
- Mauser
- Maxim Defense Industries
- MAXSafes
- MDT
- Mec-Gar
- Mec-Gar USA
- Mechanix Wear
- Meprolight
- Mesa Tactical
- MGW Armory
- Midwest Industries
- Military Arms Corporation
- Military Systems Group
- Mission First Tactical
- Mossberg
- Namaste Arms
- NCSTAR
- Nemo Arms
- NeoMag
- New Republic
- NextLevel Training
- Nightstick
- Nine-Reloaded
- NOCPIX
- Nordic Components
- Norma
- North American Arms
- North American Rescue
- Nosler
- Noveske
- OA Defense
- Odin Works
- Ohio Ordnance Works, Inc
- Otis Technology
- Otter Creek Labs
- Outdoor Edge
- Outers
- Owl & Anchor
- Pachmayr
- Palmetto State Armory
- Pathfinder
- Patriot Ordnance Factory
- Pearce Grip
- Phase 5 Weapon Systems